An Etymological Dictionary of the German Language/Annotated/Schmuck
Schmuck, masculine, ‘adornment, finery,’ Modern High German only, in Middle High German gesmuc, ‘adornment, embellishment,’ allied to schmücken, Middle High German smücken, ‘to wind, press close, dress, adorn.’ The Teutonic root smug (pre-Teutonic smuk) in schmiegen, of which schmücken is an intensive form, was frequently used originally to form words signifying ‘to dress,’ and is also found in the name of a sort of under-garment or shirt, Old High German smoccho, Anglo-Saxon smocc (compare English smock). The adjective schmuck, ‘tidy, smart,’ Modern High German only, is derived from Low German (compare North Frisian smok), whence also English smug (or from Danish smuk).